Protractor for laying off lines, angles, and elevations in building and similar work



A. R. SMITH.

PROTRACTOR FOR LAYING OFF LINES, ANGLES, AND ELEVATIONS IN BUILDING ANDSIMILAR WORK'L APPLICATION FILED JAN. 20.1921.

1,401,200. Patented Dev. 27, 1921.

UNITED STATES PATENT QZ FEQE.

ARTHUR R. SMITH, OF NEW ALBANY, INDIANA.

PROTRACTOR FOR LAYING OFF LINES, ANGLES, AND ELEVATIONS IN BUILDING ANDSIMILAR WORK.

'Specification of Letters Patent. Patented Dec. 2'7, 1921.

Application filed January 20, 1921. Serial No. 438,768.

To all w ham it may concern Be it known that I, ARTHUR B. SMITH, acitizen of the United States, and resident of New Albany, in the countyof Floyd, State of Indiana, have invented certain new and usefulImprovements in Protractors for Laying off Lines, Angles, and Elevationsin Building and Similar Work, of which the following is a specification.

This invention resides in a simple, light, easily portable device foruse by builders and contractors and others engaged in analogous work andwho are not skilled engineers or,

provided with expensive scientific instruments in practically andeiiiciently laying off or determining the desired lines, angles andapproximate elevations necessary .in their work. It is designed to saveat least part of the time required. and trouble encountered heretoforein doing such work and t enable the work to be done more accurately aswell as more rapidly. The novel features of the device will beunderstood from the following description and claims taken with thedrawings. In the drawings:

Figure l is a perspective view of a device embodying my inventionsuspended on a line ready for use, the line being partly broken away forclearness;

Fig. 2 is a top plan view of the lower longitudinal arm or member of thedevice shown separately;

Fig. 3 is a cross section through the two arms and their pivotconnection, the arms being in this instance one above the other andparallel;

Fig. at is a side view of a modified construction where the two armsshown parallel in full lines are made in sections and provided withhinges near their centers for folding into the position shown in dottedlines;

Fig. 5 is a similar view of another modification in which each arm ismade of a tubular central portion in which the end porticnstelescopically slide;

Fig. 6 is a detached side view of a portion of the longitudinal arm ormember at one end showing thehooked support engaging the supporting lineand the clamping screw to prevent end movement;

Fig. 7 is an end view of what is shown in Fig. 6;

Fig. 8 is a detached side view of a portion of the longitudinal arms atthe opposite end from that illustrated in Fig. 6 showing the hookedsupport engaging the line:

Fig. 9 is a side view of what is shown in Fig. 8, and

Fig. 10 is a top plan view of the cross arm detached.

As will be seen by reference to Fig. 1 the particular embodiment of theinvention thereshown includes an upper cross arm a made in the form ofan elongated fiat strip of wood or other suitable material and a lowerslightly longer longitudinal arm or member 6 also made in the form of anelongated flat strip of suitable material such as wood. These two armsare pivoted together so as to permit relative rotary turning to bringthem into any desired angular relation and the lower arm has concentricwith the pivot semicircular side extensions and the upper arm has a sidenotch or cutaway portion with a concentric circular inner surface. Thepivot is preferably not midway of the length of the arms but in eachcase is somewhat nearer one end than the other as shown. To secureproper balance however the pivot is in the longitudinal center line ofeach and the material of the arms on opposite sides is so proportionedthat the center of the pivot connection is approximately the center ofgravity of'each arm. This may be accomplished by cutting away the sidesof the arms the necessary amounts toward their ends as shown leaving thecentral parts fullwidth.

The cross arm a has secured to its under surface around the pivot avernier which is in the form of a metal plate such as brass makingcontact on its lower surface with the top of. the lower arm 6 as shownin Fig. 2 and having a circular margin forming the visible bottom in thenotch or cutaway portion of the upper arm a and projecting circularlytherefrom. The lower longitudinal arm or member has secured to its uppersurface concentric with the pivot and lying partly on the semicircularside extensions a circular plate having a circular inner marginsurrounding the outer margin of the vernier and is in the form of aprotractor with the necessary markings. It will of course be understoodthat the markings on the Vernier and protractor are such as to indicatethe angular relations of the arms a and b. The pivot connection betweenthe members consists of an interiorly screw threaded thimble m extendingupwardly in a hole in the lower arm and provided with a lateral. flangeat its lower end hearing on the lower surface of arm I) and anexterior-iv threaded thumb screw 6 entendingg downwardly through a holein arm (a and engaging thethreads of thimble m and havinpjan upperenlarged head eX- tending; laterally over engaging the upper surface ofthe upper arm a. .lt-W1ll he noted tint this thumb connection permitseasy cl Q grether .'n any adjusted position but when released permitsfreeturning. The thumb nut 6 preferably has a central hole or borelongitudinally thereof all the way through both arms whereby a pin orten penny nail 1 may pass down through it With its point n bGlOW thedevice as shown in r 3 and that pin or nail may be driven ilto the topof a Wooden stake or other duel object support the device.

near its ends small and short similar upwardly projecting pins arrangedin a central iosition laterally and inline with the of the pivotconnection. These are "is the operator when the device is to the rig-htposition in use to lo- Eiccuratelv the angle indicated by ts or pins.The oWer arm 1 "us "for engaging a stretched wire, cord or similarelement to support the apparatus. in the form shown these supportsconsist of all metal rods screwed into the upper face of arm 6 and haviitheir upper ends bent over into a transverse V shaped hook the innerpoints of the V beingin each case on the center line of the arm 5 and inline I mounted 1n or along; the top oi the upper with the center of thepivot connection between the arms. It w ll thus be observed that theinclined surfaces of the hooks Will cause them to slide automatically bythe action of gravity on the it is at'the' porting 'tl vr're or corduntil apeuand in the enact center supe arm (5 parallel to and with itsin the same vertical plane as said This hook arrangement perand accurateapplication 03: the

wire but to prevent longia screw threaded clamplI passes upwardlythrough the at one end near one hook g and en- 'cs the under surface ofWire or. cord and forces up into greater frictional contact with thehook; it will he observed by comparing; Figs. 2 and 10 that the upperarm is enough shorter than arm 5 to permit it to turn to a positionabove and parallel arm 7) without striking the hooks l'nt'ae modified'Eorm shown in Fig. 4: each arm formed. of two end sections hinged.

tion as illustrated in dotted lines and ani ine of thetivo members to- Vr he upper cross arm chas on its surface 1 e along the arm a in the linetogether near the middle but at some distance from the pivot and it willbe noted that the transverse pivot line of the hinge for the upper armcis along its upper margin permitting one end section to be turned upwardon over to a horizontal position on andvsubstantially parallel to theother secthat the transverse pivot line for the hinge connection' of thelower sections constituting arm. '72 is along its lower marginpermitting down turning of one section on the other and folding them asabove indicated and as shown in dotted lines. Since'this folding maytake placefwhen thearms a and'b are parallel one above thectheritheresult is a very compact article of convenient shape and size foreasy'transportation. The thickness of the parts and the arrangement ofthe hinges are such that" the projecting thumb screw 8 and pins do notinterfere with the flat compact folding,

lnthc modification shown in 5 the central portions of arms aand Z) aretubular in form' and are pivoted together as above described as to thefirst form but it will be understood that the tubes are preferablyformed of metal. I They'may be rectangular and flattened in crosssection as shown or of an} cross sectional shape desired. In addition tothe central pivoted tubular sections 7 is shown a level 0 arm or membera by Which the operator can determine certainly Whether that arm is inan exact horizontal position. diimlljv movable eight 79 may also bemounted in or on this arm to shift the center of gravity to bring; itinto proper horiaontal position when the normal balance of the partsdoes not'do this. The presence of this level furthermore permits theuser to determine when mounted on the ire or cord or even when supportedin any other Way.

The mechanical structure and operation. or the device will be understoodfrom the above description and therefore it is only necessary todescribe the nature and manner of its use in practical Work and theadvantageous functions and results secured by it. In laying off abuilding it is always easy to determine at least one building line andinusing my inventiona line or ire is stretched taut alongthat line inhorizontal position and be ii longitudie roughly the inclination of theground yond its ends secured to stakes or other fixed supports. Theapparatus is then mounted on said line by means of hooks g and is movedlongitudinally thereon until the center of the pivot connection isdirectly over the exact corner point or end of the known line. The thumbscrew K is then tightened to prevent any longitudinal movement of thedev'ce on the taut line. The upper arm a in a horizontal position. isthen turned on its pivot until. the vernier and protractor indicate theknown angle of theside line leadin oil" from the line of the taut wireor cor l he thumb screw e of the pivot joint is then tightened to clampthe arms together at that angle to prevent turning. The side line isthen easily run and determined by means of a cord or wire stretched on aline directly over the pins or sights f on the arm and the distance tothe next corner is measured on that line. following this procedure foreach side corner and line all of them can be quickly and accurately laidout. While the apparatus is especially adapted for use in building asabove described. it is also adapted for many other uses where it isdesired to determine an angle or fix a line on a known angle. Its usesare not limited to those cases where it hangs from a stretched line evenin determining the horizontal position or angle of lines and it may beused in positions diiierent from horizontal to determine the pitch ofroots, the angle of the corners of buildings or even the incline of theground. It may be used in taking levels where great accuracy is notnecessary by merely sighting along the projecting pins f in thepreferred form the arms a and b are made of seasoned hard wood whichwhen folded together make an article about 1" wide, 2- thick and fivefeet long and the vcrnicr has about 5} exposure. In this preferred forma ten penny nail. driven down through the central opening of thumb screw0 into a stake or other fixed object will so and hold the device infixed position with out the line support and the arm a may be turned tothe desired angleand a wire or line connected to the uppe' projectingend of the nail and stretched oil at the proper un le to fix the desiredline. lVhile I have described specific embodiments of my invention itwill be understood that in its broar. .1 aspects it is not limited tothe de tails of construction. Level 0 and weight 7) may be countersunkin arm (1.

Having; described. my invention what I as new and desire to secure byLet- 'er: Patent i l. in a device of the class described the ombinationwith an elongated member, of means thereon for supporting it from andbelow a stretched wire or cord in a definite position on a verticalplane therewith, a transverse member pivoted to said elongated member toturn horizontally thereon the portions extending on opposite sides beingsuch as to balance each other, and circularly arranged scales carried bysaid members and concentric with the first point to indicate the angularrelations of the members.

2. In a device of the class described the combination with an elongatedmember, of means thereof for supporting it from and below a stretchedwire or cord in a definite fixed position on a vertical plane therewitha transverse member pivotedv to said elongated member to turnhorizontally thereon, the portions extending on opposite sides beingsuch asto balance each other, and circularly arranged scales carried bysaid members and concentric with the first point to in dicate theangular relations of the members and means for clamping said transversemember in adjusted position. I

3. In a device of the class described the combination with an elongatedmember, of means thereon for supporting it from and below a stretchedwire or cord in a definite fixed position on a vertical plane therewith,

a transverse member pivoted to said elongated member to turnhorizontally thereon, the portions extending on opposite sides beingsubstantially balanced normally, a level on said transverse member,longitudinally movable means on said transverse member for so regulatingthe balance as to make said transverse member rest in a horizontalposition, and scales carried by said members concentric with the pivotpoint to indicate the angular relations of the members.

4:. In a device of the class described, the combination with anelongated member, of means thereon for supporting it from and below astretched wire or cord comprising upwardly extending hook members nearits ends having contact surfaces inclined upwardly to sharp V-shapedpoints at the cen ter, an adjustable clamp cooperating with one of saidhooked members to so engage the wire or cord as to prevent longitudinalmovement, a cross member having upwardly projectingsights thereon nearits ends and pivoted to said elongated member in the line of said sightsand in the line of the sharp points of said hooks for rotary movementthereon in a horizontal plane and cooperating means on said elongatedand cross members concentric with the pivot point to indicate theangular relations of the members.

5. In a device of the class described, the combination with an elongatedmember, of means thereon for supporting it from and below a stretchedwire or cord comprising upwardly extending hook members near its endshaving contact surfaces inclined upwardly to sharp V-shaped points atthe center, an adjustable clamp coiiperating with one of said hookedmembers to so engage the

